Euclid's classic proof about the infinitude of prime numbers has been a
standard model of reasoning in student textbooks and books of elementary
number theory. It has withstood scrutiny for over 2000 years but we shall
prove that despite the deceptive appearance of its analytical reasoning
it is tautological in nature. We shall argue that the proof is more of
an observation about the general property of a prime numbers than an
expository style of natural deduction of the proof of their infinitude.